Slow-melting ice



Dec. 6, 1949 2,490,047

B8. GlLCJ-IRISIJR, ETAL SLOW-MELTING ICE Filed May 13, 1947 2 Shets-Sheet 1 o IN V EN TORS PETER J. GILCHR/JZ JR BY W/MLEV L. PARIPOTT SLOW-MELTING ICE 2 Sheets-Sheet 2 Filed May 13, 1947 QWN QQN

- it effectively a longer cooling life; and more the product of our invention comprises first,

Patented Dec. 6, 1949 UNITED STATES PATENT OFFICE SLOWV-MELTING ICE Peter S. Gilchrist, J r., and Warley L. Parrott, Charlotte, N. 0.

Application May 13, 1947, Serial No. 747,828

3 Claims. 252-67) 2 corn starch requires heating to about 165 F., while wheat flour, which contains about 10% proparticularly to incorporating in the ice a subtein and about 80% starch, requires a higher stance that prolongs melting of the ice, and abtemperature, preferably as high as the boiling sorbs and retains the ice water. 5 point of water, 212 F. After the starch has This ice water is held in contact with the ice been gelled, tap water is added to bring the mixby the absorbent material, instead of draining ,ture up to the desired volume for freezing. In off to waste as normally occurs with ice water the usual practice, the amount of Water added from untreated ice. The retained ice water, beis suiiicient to provide in the final ice an amount ing at substantially freezing temperature, proof about 1% to 5% by weight of starch (or other vides a cooling effect to the surrounding atmoscarbohydrate) and about 99% to 95% water. phere similarly to that obtained from the ice The starch and water mixture may be frozen in itself. In this manner the effective cooling life any conventional freezing or ice manufacturing of the ice is markedly extended, as will be demonequipment. strated by the data and curves discussed below. The amount of carbohydrate material to be In accordance with our invention we incorpoused in the ice depends generally upon the derate in the water, which is to be frozen to form sired degree of retardation of melting of the ice, the ice, a material which upon thawing is highly and upon economical factors, such as the cost of absorbent of the ice water. Materials that we the carbohydrate relative to the cost of the unhave found to work satisfactorily include the treated ice and the savings efiected by prolongcarbohydrates, such as for example, starch and ing the useful life of the ice. An amount of as flour obtained from corn or wheat. Other amylittle as 1% of carbohydrate material, based on laceous products, Such s p o, c ssava 0 the total weight of the treated ice, shows an other root or tuber starches may be used. Likeappreciable improvement in retardation of the Wise, Starch 0 fl ur m y, ye, and other normal melting rate or loss in Weight by melting. grains may be employed, so long as they have Amounts of 2%, 3% and 5% show marked imthe above described properties, upon thawing, of provements, and in most cases it is not necesproducing a hydrophilic material and preferably sary to use more than about 5% as a maximum. one that swells or becomes spongy so as to in- Graphic illustrations of the improvements obcrease greatly its water absorbent and retaining tained by using 1% to 5% of corn starch, as c p y compared with untreated ice, are shown in the Corn starch and self-rising wheat flour are accompanying drawings in which: examples of materials that work very satisfac- Fig. 1 is a series of curves illustrating the t r lyrn St h, for mple, when used in differences in melting rates of the ice containing accordance with our invention, producesaspongy 0%, 1%, 3% and 5%, respectively, of starch; mass that holds a relatively great amount of and, water and will retard the melting of the ice or Fig. 2 is a similar series of curves illustrating semi-frozen water for a number of hours beyond the differences in melting rates of the ice conthe normal melting time. taining 0%, 2% and 5% starch.

The general procedure followed in preparing The curves shown in Figs. 1 and 2 are based upon melting tests carried out on 300 pound blocks of ice, containing the respective per- Our invention relates to treating ice to give making a paste of the amylaceous material by w n out the s h n a mall q n i y f centages of starch indicated. The starch was water, then adding more water and stirring to gelled and then incorporated in the ice in the Produce a fluid mixture, and e ting this mixmanner described above and the ice blocks frozen ture for a sufiicient length of time to rupture the in conventional ice making equipment. The starch granules and produce good gelation of frozen blocks were then placed in a large room the starch. The temperature required for this in which the temperature was about F. to gelling treatment will vary with the types of F., and permitted to melt in normal manner. amylaceous materials used. For example, pearl 50 The blocks were weighed at frequent intervals percentages of their original weight:

Per cent 1% starch 10 3% starch 50 5% staroh. 17

Referring to Fig. 2 in the drawings, it will be noted that the untreated ice, containing 0,% starch, was completely melted, that is, had lost 100% of its original weight, in 140 hours. At this same period, the treated ice containing 2% of starch, had lost 72% in weight; and the treated ice containing 5% of starch, had lost only 28% of its original weight. And even at' 20 01l,1 our s, this treated ice containing 5% starch, had lost only 35% of its original weight.

The slow melting ice of our invention may be used for refrigeration purposes in general. it

is particularly :useful where ice :is used blflK or large quantities, such as for example, in the refrigeration of railway freight cars carrying fruits and vegetables or other perishable prodnets. The prolonged life of this treated ice will enable the iced freight cars to travel very much 4 longer distances without reicing; thus effecting substantial savings in time and labor.

Various changes and modifications may be made in the above described materials and procedures without departing from the scope of our invention as defined in the appended claims.

We claim:

1. An article of manufacture consisting of ice and about 1% to 5%, by weight, of a gelatinized starch dispersed therethrough for effectively prolonging the melting of the ice.

2. An article of manufacture consisting of ice and about 1% to 5%, by weight, of a gelatinized pom starch,.dispersed therethrough for-reflective- 1y prolonging the melting -of the ice.

3. An article of manufacture consisting of ice :and about 1% to 5%, by weight, of gelatinized wheat flour dispersed therethrough for eifective- 'ly prolonging the melting of the ice.

ZPETER S. GILCHRIST, JR.

WARLEY L. PARROTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES "PATENTS Number Name Date 1,123,537 Huizer :5, F1915 1,861,957 De .Remer mu-W.-- June '1, 1932 2,203,230 Nitsche V .June 4, 1940 

